Baby only feeds for 10 minutes ... Is this enough?

LM :)
Hi Ladies,
My LO is 2 weeks old today and only feeds for about 10minutes at a time (sometimes 15minutes if he's really hungry). I try and feed him every 3 hours during day-time and 4 hours at night - need to wake him as he loves to sleep :) 
I'm worried this might not be enough? What is the average time for a 2 week old baby to feed?
He has more than enough wet diapers throughout the day, at least one every time 2-3hours.